1. Field of the Invention
The present invention relates generally to a wireless communication system and, more particularly, to an operating mode transition method and control apparatus for power saving of a mobile station in a wireless communication environment.
2. Description of the Related Art
Reduction of power consumption in a mobile station is of paramount importance for mobility support in a wireless communication environment.
To reduce power consumption in a mobile station, sleep mode or idle mode operations have been introduced between a mobile station and base station.
In a sleep mode or an idle mode, a mobile station does not perform active operations such as data transmission or data reception. Instead, a real-time clock and phase locked loop are driven, and periodically the mobile station wakes up to scan neighbor base stations or to perform a ranging or handover procedure.
However, in the current specification for broadband wireless access systems, the sleep mode and the idle mode are described separately, and transitions between the idle, sleep and normal modes are not described in detail. According to the specification, a mobile station in the idle mode must wake up to perform signaling operations with the corresponding base station, resulting in unnecessary power consumption of the mobile station. Further, rapid movement of the mobile station in the idle mode may cause frequent idle mode handover, and repeated performance of a ranging procedure may be necessary for network re-entry or location update, thereby consuming more power of the mobile station.